DE2536404

Acidic solutions for selectively stripping tin or tin-lead alloys from copper substrates comprising an aqueous solution of at least one nitro-substituted aromatic compound; an inorganic acid capable of readily reacting with tin and lead to form water-soluble salts thereof and incapable of reacting w...

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Bibliographische Detailangaben
1. Verfasser:	BRINDISI JUN., FRANK ANTHONY, MADISON, CONN., US
Format:	Patent
Sprache:	eng
Schlagworte:	CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS CHEMICAL SURFACE TREATMENT CHEMISTRY CLADDING OR PLATING BY SOLDERING OR WELDING COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL COATING MATERIAL WITH METALLIC MATERIAL COATING METALLIC MATERIAL CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING DIFFUSION TREATMENT OF METALLIC MATERIAL ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR ELECTRICITY INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL MACHINE TOOLS MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS METAL-WORKING NOT OTHERWISE PROVIDED FOR METALLURGY MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLICMATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASSC23 AND AT LEAST ONEPROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25 NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE PERFORMING OPERATIONS PRINTED CIRCUITS SOLDERING OR UNSOLDERING TRANSPORTING WELDING WORKING BY LASER BEAM
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Beschreibung
Zusammenfassung:	Acidic solutions for selectively stripping tin or tin-lead alloys from copper substrates comprising an aqueous solution of at least one nitro-substituted aromatic compound; an inorganic acid capable of readily reacting with tin and lead to form water-soluble salts thereof and incapable of reacting with tin and lead to form a water-insoluble compound film on the tin or tin-lead alloy surface, preferably fluoboric acid; a thiourea; an organic acid of the formula RCOOH wherein R is 1-2C alkyl or hydrogen; and a haloacetic acid wherein the halogen is chloro or bromo. The haloacetic acid in combination with the acid of the formula RCOOH result in a pronounced synergism in accelerating the rate of stripping the tin or tin-lead alloy deposit from the copper substrate.